Dozens of people are protesting the opening of Milan's Expo 2015, torching parked cars, smashing bank and store windows and clashing with riot police far from the world's fair sprawling grounds.

Protesters split off from a generally non-violent march Friday, a few hours after Italian Premier Matteo Renzi inaugurated Expo, which runs through October and features pavilions from nations large and small, rich and poor.

Continue Reading Below

Police fired tear gas and unleashed water from trucks to try to scatter the violent protesters in downtown Milan. Hooded protesters tossed bottles and incendiary devices at police and journalists, set rubbish bins afire and smashed pavement. Firefighters worked to extinguish the blazes.

Some marchers' placards protested a high-speed rail line construction in northern Italy as well as Expo and other "big projects."